U.S. Pat. No. 3,799,758 issued to John E. Franz on Mar. 26, 1974 describes the preparation and herbicidal utility of N-phosphonomethylglycine and its esters, amides, and salts.
U.S. Pat. No. 4,120,689 issued to Gerard A. Dutra on Oct. 17, 1978 describes alkyl-[di-(benzyl) or di-(aryl)] esters of N-phosphonomethylglycine which are produced by the reaction of a dibenzyl or diaryl phosphite with an N-methylene alkyl glycinate trimer. These esters and the hydrolysis products thereof containing at least one benzyloxy or aryloxy group bonded to phosphorus are compounds disclosed as having the Formula I ##STR1## wherein
Re is a member of the group consisting of phenyl, benzyl, naphtyl, biphenyl, and phenyl, benzyl or naphthyl groups substituted with from 1 to 3 groups selected from the class consisting of hydroxyl, lower alkyl, lower alkoxy, lower alkylthio, trifluoromethyl, carbo (lower alkoxy), nitro or halo;
R.sub.1 is hydrogen or an R group; and
R.sub.2 is a lower alkyl group or hydrogen, and the strong acid salts of the compounds wherein neither R.sub.1 or R.sub.2 is H. These compounds are useful as postemergent herbicides.
U.S. Pat. No. 4,067,719 issued to Gerard A. Dutra on Jan. 10, 1978, discloses esters of N-phosphonomethylglycinonitriles which are produced by the reaction of a diaryl phosphite with an N-methylene glycinonitrile trimer. These compounds and the hydrolysis products thereof are disclosed as having the Formula II ##STR2## wherein
(Aryl) is selected from phenyl, naphthyl, or biphenyl;
each X is a substituent on said Aryl selected from halogen, alkyl of 1 to 4 carbon alkoxy and alkylthio of 1 to 3 carbons, alkoxycarbonyl of 2 to 3 carbon atoms, methylenedioxy, cyano, trifluoromethyl, or nitro;
Z is oxygen or sulfur;
a is an integer from zero to 3;
b is an integer from zero to 1;
Y is a strong acid capable of forming a salt with the amino group; and
x is zero or 2, provided that x must be zero when b is 1, as well as a process for producing such compounds. These N-phosphonomethylglycinonitriles are said to be useful as herbicides.
U.S. Pat. No. 4,089,671 issued to Gerard A. Dutra on May 16, 1978 describes N,N'-methylene-bis-[O,O-diaryl-N-phosphonomethylglycinonitriles] which can be produced concurrently with compounds of Formula II by the reaction of a diarylphosphite with an N-methylene-glycinonitrile trimer or sequentially from compounds of Formula II. These aminal derivatives are disclosed as having the Formula III ##STR3## wherein
R' is a member of the group consisting of phenyl or naphthyl and phenyl or naphthyl substituted with 1 or 2 groups selected from the class consisting of halogen, lower alkyl, lower alkoxy, and lower alkylthio. These animal derivatives of N-phosphonomethylglycinonitrile are useful as post-emergent herbicides.